refactor(hosts): make nanuqsaurus adopt default

docs/install-help.txt

@@ -9,7 +9,7 @@ Pick a stable disk path (prefer /dev/disk/by-id/*) and run:
   sudo nix --experimental-features "nix-command flakes" \
     run github:nix-community/disko/latest#disko-install -- \
     --mode format \
-    --flake "git+https://codeberg.org/<owner>/<repo>.git#nanuqsaurus" \
+    --flake "git+https://codeberg.org/<owner>/<repo>.git#nanuqsaurus-btrfs" \
     --disk main /dev/disk/by-id/<your-disk> \
     --mount-point /mnt
 

hosts/nanuqsaurus-btrfs.nix

@@ -0,0 +1,34 @@
+{
+  config,
+  pkgs,
+  lib,
+  inputs,
+  ...
+}:
+
+{
+  imports = [
+    inputs.disko.nixosModules.disko
+    inputs.lix-module.nixosModules.lixFromNixpkgs
+    inputs.nix-index-database.nixosModules.nix-index
+    inputs.nix-flatpak.nixosModules.nix-flatpak
+    ../modules/system/flatpak.nix
+    ../modules/system/base.nix
+    ../modules/system/disko-btrfs.nix
+    ../modules/system/packages.nix
+    ../modules/system/shell.nix
+    ../modules/system/home-manager-skel.nix
+    ../modules/system/fonts.nix
+    ../modules/system/printer.nix
+    ../modules/desktop/desktop-entries.nix
+    ../modules/desktop/file-manager.nix
+    ../modules/desktop/gnome-minimal.nix
+    ../modules/development/flox.nix
+    ../modules/users/admin.nix
+    ./nanuqsaurus-hardware.nix
+  ];
+
+  networking.hostName = "nanuqsaurus";
+
+  system.stateVersion = "25.11";
+}

hosts/nanuqsaurus.nix

@@ -8,13 +8,11 @@
 
 {
   imports = [
-    inputs.disko.nixosModules.disko
     inputs.lix-module.nixosModules.lixFromNixpkgs
     inputs.nix-index-database.nixosModules.nix-index
     inputs.nix-flatpak.nixosModules.nix-flatpak
     ../modules/system/flatpak.nix
     ../modules/system/base.nix
-    ../modules/system/disko-btrfs.nix
     ../modules/system/packages.nix
     ../modules/system/shell.nix
     ../modules/system/home-manager-skel.nix
@@ -25,10 +23,52 @@
     ../modules/desktop/gnome-minimal.nix
     ../modules/development/flox.nix
     ../modules/users/admin.nix
-    ./nanuqsaurus-hardware.nix
   ];
 
   networking.hostName = "nanuqsaurus";
 
+  # Minimal defaults for adopting an existing disk layout.
+  # Override these in a site-local host module if your layout differs.
+  boot.initrd.availableKernelModules = lib.mkDefault [ "ahci" "xhci_pci" "virtio_pci" "sr_mod" "virtio_blk" ];
+  nixpkgs.hostPlatform = lib.mkDefault "x86_64-linux";
+
+  fileSystems."/" = lib.mkDefault {
+    device = "/dev/disk/by-partlabel/disk-main-nixos";
+    fsType = "btrfs";
+    options = [
+      "x-initrd.mount"
+      "compress=zstd"
+      "subvol=root"
+    ];
+  };
+
+  fileSystems."/home" = lib.mkDefault {
+    device = "/dev/disk/by-partlabel/disk-main-nixos";
+    fsType = "btrfs";
+    options = [
+      "compress=zstd"
+      "subvol=home"
+    ];
+  };
+
+  fileSystems."/nix" = lib.mkDefault {
+    device = "/dev/disk/by-partlabel/disk-main-nixos";
+    fsType = "btrfs";
+    options = [
+      "x-initrd.mount"
+      "compress=zstd"
+      "subvol=nix"
+    ];
+  };
+
+  fileSystems."/boot" = lib.mkDefault {
+    device = "/dev/disk/by-partlabel/disk-main-ESP";
+    fsType = "vfat";
+    options = [
+      "fmask=0022"
+      "dmask=0022"
+    ];
+  };
+
   system.stateVersion = "25.11";
 }

scripts/install-btrfs.sh

@@ -9,7 +9,7 @@ set -euo pipefail
 #   - github:<owner>/<repo>
 
 DISK="${DISK:-/dev/vda}"
-TARGET_HOST="${TARGET_HOST:-nanuqsaurus}"
+TARGET_HOST="${TARGET_HOST:-nanuqsaurus-btrfs}"
 FLAKE="${FLAKE:-}"
 
 MNT=/mnt